ABSTRACT
Figure 1. Regions of acute and chronic hypoxia can develop within solid tumors. A) Acute hypoxia occurs as a result of sudden and temporary changes in blood fl ow (e.g., collapsed blood vessels). Subsequent reoxygenation leads to cyclic hypoxia and the generation of reactive oxygen species (ROS). B) Solid tumors can often have uneven distribution of blood vessels leading to chronic or diffusion-limited hypoxia in cells >150 µm from blood vessels near the diffusion limit of oxygen.
